Quantification of the acute effect of a low dose of red wine by nonlinear measures of RR and QT interval series in healthy subjects

• We compared the acute effect of red wine and control alcoholic drink on the heart rhythm properties.
• Nonlinear analysis of RR and QT series reveals the difference between the effects of wine and the control drink.
• Wine changed the complexity of series, while the control drink prolonged QT and RR intervals.

The measures of nonlinear properties of RR interval and QT interval time series are sensitive to physiologically- or pathologically-induced complexity/regularity changes, but were not used to estimate the effect of alcohol intake. We wanted to examine the potential of these measures to quantify the acute effect of a low dose of red wine in healthy subjects. In separate experiments, fourteen young volunteers drank 200 ml of red wine and a control drink with equal concentration of ethanol. ECG in supine position was recorded 20 min before and 60 min after drink intake. RR interval and QT interval series were extracted from ECG and we calculated variability, scaling exponents (α1 and α2) and sample entropy (SampEn) for both series. Systolic and diastolic blood pressures (BP) were measured every 10 min. The immediate effect of both the drinks was equal: HR, BP and QT variability exhibited a sudden increase and then a decrease. However, the prolonged effect of wine and the control drink was different. Wine decreased both BP (p<0.05) and reduced complexity of RR and QT series (increased scaling exponents and decreased SampEn). The control drink prolonged QT and RR intervals (p<0.05). These results point out that the nonlinear properties of RR and QT interval series could be used to differentiate the effect of wine and ethanol. Changes in RR and QT interval series induced by a low dose of red wine are more detectable by methods that quantify the structure of the series than by methods that quantify their variability.